If these negotiations fail, you must respond to the eviction suit. You will be served with a copy of your landlord's eviction complaint. The reasons for the eviction will be included in this complaint, and often if you satisfy the claim the landlord has against you (e.g. by paying the rent), the suit will be dismissed. This service will also include the date of the hearing, and you will have to show up to the hearing to argue your side.
At this point, you may wish to seek the advice of an experienced Indiana evictions lawyer, either to help you defend against the eviction or to advise you as to any rights you may have with respect to the circumstances surrounding the notice and the unlawful detainer action.